Telecommunications switching platforms operate to connect incoming communication channels to selected outgoing communication channels. This switching is generally done in response to phone numbers dialed by the users or subscribers of the company operating the telecommunications system, or by others who are calling these subscribers. For example, the caller enters a phone number and signaling is sent along with or over the communication channel and the telecommunication system attempts to establish an end-to-end communications link to the destination number that the caller has dialed.
Certain support functions are generally provided by a telecommunications switching platform. Specifically, the telecommunications switching platform decodes signaling generated in response to keys input by the caller/subscriber so that the caller's voice channel may be connected to an appropriate destination information channel. In the process of connecting, other tones may be provided to the caller/subscriber. Specifically, if the switching platform is unable to connect the caller to the requested destination because the connecting trunk is busy, the switching platform provides the trunk busy tone. For incoming calls, the switching platform sends normal busy signals back to the far side connection if the local loop for the called party is busy. If the local loop or subscriber loop is not busy, the switching platform will send a ring signal until the subscriber answers. Thus, the switching platform will provide a number of different tones during the intermediate process of making end-to-end switching connections.